1. Field of the Invention
The present invention relates to communication systems, and in particular to initiation of service provisioning, requiring communications between entities associated with the communication system.
2. Description of the Related Art
A communication system can be seen as a facility that enables communication between two or more entities such as user equipment, communication network elements and other entities associated with the communication system. A communication system typically operates in accordance with a given standard or specification which sets out what the various entities associated with the communication system are permitted to do and how that should be achieved. For example, the standard or specification may define whether the user, or more precisely, user equipment or terminal is provided with a circuit switched service and/or a packet switched service. Communication protocols and/or parameters which shall be used for the connection may also be defined. In other words, a specific set of “rules” on which the communication can be based on needs to be defined to enable communication by means of the system.
Communication systems providing wireless communication for the user equipment are known. An example of the wireless systems is a cellular network. In cellular systems, a base transceiver station (BTS) or similar access entity serves mobile stations (MS) or other such wireless user equipment (UE) via a wireless interface between these entities. The communication between the user equipment and the elements of the communication network can be based on an appropriate communication protocol. The operation of the base station apparatus and other apparatus required for the communication can be controlled by one or several control entities. The various control entities may be interconnected. One or more gateway nodes may also be provided for connecting the cellular network to other networks. e.g. to a public switched telephone network (PSTN) and/or other communication networks such as an IP (Internet Protocol) and/or other packet switched networks.
An example of the services that may be offered for the subscribers to a communication system are so called multimedia services. Communication systems enabled to offer the multimedia services are sometimes referenced to as IP Multimedia networks. IP Multimedia (IM) functionalities can be provided by means of a IP Multimedia Core Network (CN) subsystem, or briefly IP Multimedia subsystem (IMS). The IMS comprises various entities for the provision of the multimedia services.
The communication systems have developed in the direction wherein various service provision functions of the network are handled by network entities known as servers. For example, in the current third generation (3G) wireless multimedia network architectures it is assumed that several different servers are used for handling different functions. These include functions such as the call session control functions (CSCFs). The call session functions may be divided into various categories such as a proxy call session control function (P-CSCF), interrogating call session control function (I-CSCF), and serving call session control function (S-CSCF). It shall be appreciated that sometimes the CSCFs may be referred to as call state control functions or call server functions.
The serving call session control function forms the entity the subscriber needs to be registered at in order to be able to request a service from the communication system. The serving call session control function can be divided further between originating call session control function (O-CSCF) and terminating call session control function (T-CSCF) at the originating and terminating ends of a session.
In addition to the serving control entity, the user may need to be associated with proxy control entity, such as the P-CSCF. The proxy entity may be assigned to an area where the user is serviced.
Entities such as a home subscriber server (HSS) and various application servers may also be provided in the communication network. From the above mentioned servers the home subscriber server (HSS) is for storing subscriber related information. The subscriber information may include information such as authentication data (e.g. registration identities of the subscriber or the terminals) and so on. The HSS is typically used for storing permanently subscriber profile information. The home subscriber server (HSS) can be queried by other function entities, e.g. during session set-up procedures.
An application server (AS) is an entity adapted to offer value added IM services for the users. An application server may reside in the user's home network. The application server may also, alternatively, be external to the user's home network, and be provided by a third party service. The third party could be another network or simply a stand-alone application server. An Application Server may influence and impact a data communication session on behalf of the services supported by the operator's network. An application server may host and execute services. Examples of the application servers include Session Initiation Protocol (SIP) Application Servers, Open Service Access (OSA) Application Servers, and Customized Applications for Mobile network Enhanced Logic IP Multimedia Service Switching Functions (CAMEL IM-SSF).
Traditionally communication systems are arranged such that a user, typically a subscriber, has to initiate communications over the communication system. For example, a user may request a session, transaction or other type of communications from an appropriate communications network entity. Such communications can be seen as originating from the user.
Thus, originating sessions/transactions are understood as sessions/transactions that are normally originated by the user equipment of the user or by a network entity on behalf of the user. Terminating sessions/transactions are sessions/transactions that are normally terminated by the user equipment of the user or by a network entity on behalf of the user.
For example, Standards for the 3GPP (Third Generation Partnership Project) release 5 (Rel-5) IMS networks define rules for how the user equipment (ULE) can originate sessions and single transactions. However, the only rules given in the Rel-5 concentrate on how the so-called originating filtering criteria is applied. Release 5 does not enable any other party to originate the session or transaction on the behalf of the user. Release 6 of the 3GPP standards require that the application server (AS) must be able to send session initiation protocol (SIP) requests on behalf of the user equipment via an ISC (IP Multimedia Service Control) interface to the S-CSCF. However, even the current release 6 of the 3GPP standards does not provide any mechanism for the application server (AS) that would enable the application server to do so, other than in exceptional cases where the application server originated requests are directly triggered by requests originated from a user equipment. Therefore the application server is still not able to run services which generate SIP requests or other request on behalf of the user.
The inventors have found that it may be advantageous if network entities such as the application servers could initiate processes requiring communications on behalf of the user such that the user could be seen-as being the originating party. An example of services where this could be useful include messaging lists wherein the application server could sent messages to the members of the list on the behalf of the user. Another example is an application server that could send on the behalf of the user messages communicating the presence status of the user. A still further example is an application that could start sessions or transactions on behalf of the user for example for conference or group calls or for chat applications. It shall be appreciated that the above lists only few examples, and that there are various other services that might benefit from the possibility of a network entity being enabled to originate requests for communications.
However, due to the lack of a mechanism for handling the network entity originated requests such operation might cause problems in the present communication systems. Problems may arise, e.g., with regards to routing of subsequent communications, charging functions and so on. This occurs since the other entities of the communication system may not know, e.g., where to communicate any further messages or how to control the communications.
For example, when a S-CSCF receives a message it needs to be able to make a decision how to treat the message. In the current systems the S-CSCF may apply filter criteria known as ‘originating filter’ and ‘terminating filter’ to the message.
The term ‘filter criteria’ (FC) refers to information that defines the relevant Service Point Triggers (SPTs) for a particular service application. In the SIP communication environment the filter criteria define the subset of SIP requests received by the S-CSCF that should be sent or proxied to a particular service application. The S-CSCF may receive the filter criteria from the home subscriber server (HSS) or the application server (AS).
In the prior art, terminating filter criteria are applied to all messages from the application server. However, the message may be an application server originated service request or other such message that is originated on the behalf of the user in the network. Thus the inventors have found that a mechanism is required for deciding if originating filter criteria shall be applied to the message instead of the terminating filter criteria. This is because the originating filter criteria may give more accurate evaluation results for such messages.
If the wrong “role,” i.e. filter criteria, is used for the message, this may cause problems, e.g., in the view of routing and other control operations. Once a decision is made in this regard, the decided role may also need to be communicated to other entities of the communication system so that they may apply a proper filter criteria for evaluation of messages that originate from an entity that is other than a user on the behalf of whom the message is sent.